Add the compatible for the Raspberry Pi AUX UART and an init function which
enables it via the aux register and configures the correct shift value.
Signed-off-by: Rouven Czerwinski <r.czerwinski@xxxxxxxxxxxxxx>
---
drivers/serial/serial_ns16550.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 8ddcfdb..ccd082e 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -253,6 +253,23 @@ static void ns16550_jz_init_port(struct console_device *cdev)
ns16550_serial_init_port(cdev);
}
+#define BCM2836_AUX_CLOCK_ENB 0x3f215004 /* BCM2835 AUX Clock enable register */
+#define BCM2836_AUX_CLOCK_EN_UART BIT(0) /* Bit 0 enables the Miniuart */
+
+static void rpi_init_port(struct console_device *cdev)
+{
+ struct ns16550_priv *priv = to_ns16550_priv(cdev);
+
+ writeb(BCM2836_AUX_CLOCK_EN_UART, BCM2836_AUX_CLOCK_ENB);
+ priv->plat.shift = 2;
+ /*
+ * We double the clock rate since the 16550 will divide by 16
+ * (instead of 8 required by the BCM2835 peripheral manual)
+ */
+ priv->plat.clock = priv->plat.clock*2;
+ ns16550_serial_init_port(cdev);
+}
+
/*********** Exposed Functions **********************************/
/**
@@ -353,6 +370,11 @@ static __maybe_unused struct ns16550_drvdata tegra_drvdata = {
.linux_console_name = "ttyS",
};
+static __maybe_unused struct ns16550_drvdata rpi_drvdata = {
+ .init_port = rpi_init_port,
+ .linux_console_name = "ttyS",
+};
+
static int ns16550_init_iomem(struct device_d *dev, struct ns16550_priv *priv)
{
struct resource *iores;
@@ -528,6 +550,12 @@ static struct of_device_id ns16550_serial_dt_ids[] = {
.data = &jz_drvdata,
},
#endif
+#if IS_ENABLED(CONFIG_MACH_RPI_COMMON)
+ {
+ .compatible = "brcm,bcm2835-aux-uart",
+ .data = &rpi_drvdata,
+ },
+#endif
{
/* sentinel */
},
--
git-series 0.9.1
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